Enclosure for battery cell comprising quenched steel

Abstract

The invention relates to an enclosure for a battery cell comprising quenched steel. A method for manufacturing a tubular housing of a battery cell includes roll-forming a steel sheet into a tubular body. The steel includes 0.02 wt% to 0.3 wt% of carbon, 0.2 wt% to 2.0 wt% of manganese, 0.5 wt% to 3.0 wt% of at least one of chromium and molybdenum, 0.2 wt% to 2.0 wt% of silicon, 0.01 wt% to 0.2 wt% of at least one of niobium, titanium and vanadium, and iron. The method includes welding sides of a tubular body to form a weld seam, heating the tubular body to a temperature of 900 DEG C to 950 DEG C, and quenching the tubular body.

Description

Technical Field

[0001] This disclosure relates to battery cells for a battery pack, and more particularly to a housing for a battery cell of a battery pack that includes hardened steel. Background Art

[0002] The information provided in this section is for a general introduction to the background of this disclosure. The work of the currently named inventors described in this section, and aspects of the specification that may not otherwise be determined to be prior art at the time of filing, are not expressly or impliedly admitted to be prior art for this disclosure.

[0003] Electric vehicles (EVs), such as battery electric vehicles (BEVs), hybrid vehicles, and / or fuel cell vehicles, include one or more electric motors and a battery pack system that includes one or more battery cells, modules, and / or packs. A power control system is used to control the charging and / or discharging of the battery pack system during charging and / or driving.

[0004] A battery cell includes one or more cathode electrodes, anode electrodes, and separators disposed within a battery cell housing. The cathode electrode includes a cathode active material layer disposed on a cathode current collector. The anode electrode includes an anode active material layer disposed on an anode current collector. Summary of the Invention

[0005] A method for manufacturing a tubular housing for a battery cell includes rollforming a steel sheet into a tubular body. The steel includes 0.02 to 0.3 wt% carbon, 0.2 to 2.0 wt% manganese, at least one of 0.5 wt% to 3.0 wt% chromium and molybdenum, 0.2 wt% to 2.0 wt% silicon, at least one of 0.01 wt% to 0.2 wt% niobium, titanium, and vanadium, and iron. The method includes welding the sides of the tubular body to form a weld seam, heating the tubular body to a temperature of 900°C to 950°C, and quenching the tubular body.

[0006] In other features, the method includes mechanically crimping and welding a bottom portion to one end of the tubular body. After quenching, the tubular body has a martensitic microstructure. The tubular body includes one or more chromium carbides having a size of 50 to 500 nm.

[0007] Among other features, after quenching, the fraction of one or more chromium carbides in the tubular body is from 1.0 vol% to 20 vol%. After quenching, the weight of one or more chromium carbides in the tubular body is from 5 wt% to 52 wt%. The tubular body has a minimum tensile strength of 800 MPa at room temperature and a minimum tensile strength of 300 MPa at 600 °C. The tubular outer casing has one of a cylindrical cross-section and a rhombic cross-section.

[0008] Among other features, the maximum hardness difference between the weld seam and the steel of the tubular body that is not thermally affected during welding is less than 50 HV. The steel includes a nickel coating and an iron-nickel alloy layer disposed between the nickel coating and the steel after quenching.

[0009] A tubular outer casing for a battery pack cell includes a tubular body made of steel and including a seam weld. The steel contains 0.02 to 0.3 wt% carbon, 0.2 to 2.0 wt% manganese, 0.5 wt% to 3.0 wt% chromium and molybdenum, 0.2 wt% to 2.0 wt% silicon, at least one of 0.01 wt% to 0.2 wt% niobium, titanium and vanadium, and iron. A bottom part attached to one end of the tubular body.

[0010] Among other features, after austenitization and quenching, the tubular body has a martensitic microstructure. After austenitization and quenching, the tubular body includes one or more chromium carbides having a size of 50 to 500 nm.

[0011] Among other features, after austenitization and quenching, the fraction of one or more chromium carbides in the tubular body is from 1.0 vol% to 20 vol%. After austenitization and quenching, the weight of one or more chromium carbides in the tubular body is from 5 wt% to 52 wt%. The tubular body has a minimum tensile strength of 800 MPa at room temperature and a minimum tensile strength of 300 MPa at 600 °C. The tubular outer casing has a prismatic cross-section.

[0012] Among other features, the tubular outer casing has a cylindrical cross-section. The maximum hardness difference between the weld seam and the steel of the tubular body that is not thermally affected during welding is less than 50 HV. The steel includes a nickel coating and an iron-nickel diffusion layer disposed between the nickel coating and the steel.

[0013] The present invention discloses the following solutions:

[0014] Solution 1. A method for manufacturing a tubular outer casing for a battery pack cell, comprising:

[0015] Rolling a steel plate into a tubular body by bending,

[0016] wherein the steel contains:

[0017] 0.02 to 0.3 wt% of carbon,

[0018] 0.2 to 2.0 wt% of manganese,

[0019] at least one of 0.5 wt% to 3.0 wt% of chromium and molybdenum,

[0020] 0.2 wt% to 2.0 wt% of silicon,

[0021] at least one of 0.01 wt% to 0.2 wt% of niobium, titanium and vanadium, and iron;

[0023] Welding the side of the tubular body to form a weld;

[0024] Heating the tubular body to a temperature of 900 °C to 950 °C; and

[0025] Quenching the tubular body.

[0026] Aspect 2. The method according to Aspect 1, further comprising attaching a bottom portion to one end of the tubular body.

[0027] Aspect 3. The method according to Aspect 1, wherein after quenching, the tubular body has a martensitic microstructure.

[0028] Aspect 4. The method according to Aspect 1, wherein the tubular body comprises one or more chromium carbides having a size of 50 nm to 500 nm.

[0029] Aspect 5. The method according to Aspect 4, wherein after quenching, the fraction of one or more chromium carbides in the tubular body is 1.0 vol% to 20 vol%.

[0030] Aspect 6. The method according to Aspect 4, wherein after quenching, the weight of one or more chromium carbides in the tubular body is 5 wt% to 52 wt%.

[0031] Aspect 7. The method according to Aspect 1, wherein the tubular body has a minimum tensile strength of 800 MPa at room temperature and a minimum tensile strength of 300 MPa at 600 °C.

[0032] Aspect 8. The method according to Aspect 1, wherein the tubular outer shell has one of a cylindrical cross-section and a prismatic cross-section.

[0033] Aspect 9. The method according to Aspect 1, wherein the maximum hardness difference between the seam weld and the steel of the tubular body not affected by heat during welding is less than 50 HV.

[0034] Aspect 10. The method according to Aspect 1, wherein the steel comprises a nickel coating and an iron-nickel alloy layer disposed between the nickel coating and the steel after quenching.

[0035] Aspect 11. A tubular housing for a battery pack cell, comprising:

[0036] A tubular body made of steel and including a seam weld,

[0037] wherein the steel contains:

[0038] 0.02 to 0.3 wt% carbon;

[0039] 0.2 to 2.0 wt% manganese;

[0040] At least one of 0.5 wt% to 3.0 wt% chromium and molybdenum;

[0041] 0.2 wt% to 2.0 wt% silicon;

[0042] At least one of 0.01 wt% to 0.2 wt% niobium, titanium and vanadium; and

[0043] Iron; and

[0044] A bottom part attached to one end of the tubular body.

[0045] Aspect 12. The tubular housing according to Aspect 11, wherein the tubular body has a martensitic microstructure after austenitization and quenching.

[0046] Aspect 13. The tubular housing according to Aspect 12, wherein the tubular body includes one or more chromium carbides having a size of 50 nm to 500 nm after austenitization and quenching.

[0047] Aspect 14. The tubular housing according to Aspect 13, wherein after austenitization and quenching, the fraction of one or more chromium carbides in the tubular body is 1.0 vol% to 20 vol%.

[0048] Aspect 15. The tubular housing according to Aspect 13, wherein after austenitization and quenching, the weight of the one or more chromium carbides in the tubular body is 5 wt% to 52 wt%.

[0049] Aspect 16. The tubular housing according to Aspect 11, wherein the tubular body has a minimum tensile strength of 800 MPa at room temperature and a minimum tensile strength of 300 MPa at 600 °C.

[0050] Aspect 17. The tubular housing according to Aspect 13, wherein the tubular housing has a prismatic cross-section.

[0051] Embodiment 18. The tubular housing according to Embodiment 11, wherein the tubular housing has a cylindrical cross-section.

[0052] Embodiment 19. The tubular housing according to Embodiment 11, wherein the maximum hardness difference between the seam weld and the steel of the tubular body that is not affected by heat during welding is less than 50 HV.

[0053] Embodiment 20. The tubular housing according to Embodiment 11, wherein the steel includes a nickel coating and an iron-nickel diffusion layer disposed between the nickel coating and the steel.

[0054] Further applicable fields of the present disclosure will be apparent from the detailed description, the claims, and the drawings. The detailed description and the specific embodiments are only intended to illustrate and are not intended to limit the scope of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] The present disclosure will be more fully understood from the detailed description and the accompanying drawings, wherein:

[0056] Figure 1 is a functional block diagram of an example of a battery pack cell including a battery pack cell stack, the battery pack cell stack including an anode electrode, a cathode electrode, and a separator disposed in a housing;

[0057] Figure 2A and Figure 2B is a perspective view of an example of a prismatic battery pack cell housing according to the present disclosure; and

[0058] Figure 3 is a side cross-sectional view of an example of a cylindrical battery pack cell according to the present disclosure;

[0059] Figure 4A is a side view of an example of a tube during induction welding according to the present disclosure;

[0060] Figure 4B is a side view of an example of a welded tube during induction heating according to the present disclosure;

[0061] Figure 5 is a flowchart of an example of a method for manufacturing a tubular housing according to the present disclosure;

[0062] Figure 6A is a scanning electron microscope image of an example of a tubular housing before hardening;

[0063] Figure 6B and Figure 6C is a scanning electron microscope image of an example of a tubular housing after hardening;

[0064] Figure 7A and Figure 7Bis a simulation indicating the estimated phase volume fraction of an example housing according to the present disclosure as a function of temperature;

[0065] Figure 8A and Figure 8B is a side sectional view showing a nickel-plated steel according to the present disclosure before and after hardening; and

[0066] Figure 9A 、 Figure 9B and Figure 9C respectively show improvements in welding quality according to the present disclosure after welding, after heating to austenitization, and after quenching and hardening.

[0067] In the drawings, reference numerals may be reused to designate similar and / or identical elements. Detailed Description

[0068] Although a battery pack housing according to the present disclosure is shown herein in the context of a vehicle, the battery pack housing can be used in stationary applications and / or other applications.

[0069] A battery pack cell includes a stack of an anode electrode, a cathode electrode, and a separator disposed in the battery pack cell stack. The battery pack cell stack is disposed in a housing that can be made of metal. For cylindrical and prismatic battery pack cells, the housing is typically made of metal such as aluminum or steel.

[0070] The melting temperature of steel is about 2.5 times higher than that of aluminum. Using steel to manufacture the housing helps to maintain the integrity of the housing during a thermal runaway event when the temperature of the housing exceeds the melting temperature of aluminum.

[0071] During thermal runaway, sidewall failure of the steel housing can still occur. For example, sidewall failure can occur in a battery pack cell having a thin steel wall (e.g., having a thickness of 0.2 mm to 0.3 mm). Although the thermal runaway temperature is typically lower than the melting temperature of steel, when the internal temperature of the battery pack cell rises above 800 °C, the housing easily ruptures due to the softening of the steel during thermal runaway. During thermal runaway, the battery pack housing experiences a temperature of about 500 °C to 800 °C. At these high temperatures, low-carbon steel softens, which can trigger sidewall rupture (e.g., due to high gas pressure). Sidewall failure can be mitigated by increasing the thickness of the housing wall. However, increasing the thickness of the housing reduces the mass energy density (Wh / kg) of the battery pack cell.

[0072] The present disclosure relates to a housing for cylindrical and prismatic battery pack cells made of a steel alloy that gradually softens as the temperature increases compared to mild steel. Reducing softening (e.g., allowing more strength to be retained at high temperatures) helps to avoid sidewall failure.

[0073] In some instances, cold-rolled and annealed steel sheets including a nickel coating are used. In some instances, the steel sheet contains 0.02 to 0.3 wt% carbon, 0.2 to 2.0 wt% manganese, 0.5 wt% to 3 wt% chromium and molybdenum, 0.2 wt% to 2 wt% silicon, at least one of niobium, titanium, and / or vanadium in an amount of 0.01 wt% to 0.2 wt%, and iron and other materials in the balance of the composition.

[0074] In some instances, the outer shell has a martensitic microstructure for room temperature strength and one or more chromium carbides (e.g., fine and / or undissolved) for high temperature properties. In some instances, the carbide fraction is 1.0 vol% to 20 vol%. In some instances, the size of one or more chromium carbides is 50 nm to 500 nm. In some instances, the chromium content of one or more chromium carbides is 5 wt% to 52 wt%. In some instances, the minimum tensile strength of the outer shell is 800 MPa at room temperature and 300 MPa at 600 °C.

[0075] In some instances, a method for manufacturing an outer shell includes roll-forming a cold-rolled and annealed steel sheet (having the components described herein) into a tube having a rectangular or cylindrical tube shape. Opposite sides of the tube shape are welded to form a tubular outer shell with open ends (e.g., using high-frequency welding or laser welding).

[0076] The tubular outer shell is rapidly austenitized using induction heating at a temperature of 900 °C to 950 °C. After heating, the tubular outer shell is quenched (using air, water, or a cooled die) to room temperature to form a martensitic microstructure with a fine dispersion of one or more chromium carbides for enhanced strength. After induction heating and quenching, the bottom part of the outer shell is welded to one end of the tubular outer shell.

[0077] Compared to aluminum outer shells currently used in prismatic batteries, the battery outer shells described herein reduce costs. Due to the relatively thin steel walls, the steel outer shells are lighter. Due to the enhanced high-temperature strength, the outer shells also improve safety. The enhanced strength inhibits sidewall rupture to provide additional time for pressure release during a thermal event.

[0078] Now refer to Figure 1, the battery cell 10 of the battery pack includes C cathode electrodes 20, A anode electrodes 40, and S separators 32 arranged in a battery cell stack 12 of the battery pack in a predetermined order, where C, S, and A are integers greater than zero. The C cathode electrodes 20-1, 20-2, ..., and 20-C include cathode active material layers 24 arranged on one or both sides of the cathode current collector 26. The A anode electrodes 40-1, 40-2, ..., and 40-A include anode active material layers 42 arranged on one or both sides of the anode current collector 46. In some examples, the A anode electrodes 40 and the C cathode electrodes 20 exchange lithium ions during charging / discharging.

[0079] In some examples, the cathode active material layer 24 and / or the anode active material layer 42 includes a coating (e.g., applied using a wet or dry roll-to-roll method) to the current collector, the coating including one or more active materials, one or more conductive additives, and / or one or more binder materials.

[0080] In some examples, the cathode current collector 26 and / or the anode current collector 46 includes a metal foil, a metal mesh, a perforated metal, a three-dimensional (3D) metal foam, and / or an expanded metal. In some examples, the current collector is made of one or more materials selected from copper, stainless steel, brass, bronze, zinc, aluminum, and / or their alloys. The external tabs 28 and 48 are respectively connected to the current collectors of the cathode electrode and the anode electrode, and may be arranged on the same side or different sides of the battery cell stack 12 of the battery pack. The external tabs 28 and 48 are connected to the terminals of the battery cell stack 12 of the battery pack.

[0081] Now refer to Figure 2A and Figure 2B , the battery cell 58 of the battery pack includes a housing 60. In some examples, the housing 60 has a prismatic shape with a rectangular cross-section in the x-axis, y-axis, and z-axis planes. In some examples, the housing 60 includes a housing body 61, and the housing body 61 includes side faces 80 corresponding to the narrow faces and side faces 82 corresponding to the wide faces. The housing body 61 defines a rectangular prism with open ends. In some examples, the housing 60 includes a lid portion 84 and a bottom portion 86. In other examples, the bottom portion 86 is attached after the housing 60 is formed. Edges 83 are arranged between the side faces 80 and 82, between the side faces 80 and 82 and the lid portion 84, and between the side faces 80 and 82 and the bottom portion 86.

[0082] The lid portion 84 and optionally the bottom portion 86 are attached to the housing body 61 to respectively close the top opening and the bottom opening of the housing body 61. The battery cell 58 of the battery pack includes external terminals 62 and 64 passing through the lid portion 84. The battery cell stack 12 of C cathode electrodes 20, A anode electrodes 40, and S separators 32 is arranged in the housing 60.

[0083] External terminals 62 and 64 are respectively connected to external tabs 28 and 48 of C cathode electrodes 20 and A anode electrodes 40. In Figure 2A , the cover portion 84 does not include a pressure-based vent cap. In Figure 2B , the cover portion 84 (and / or the bottom portion 86) includes a pressure-based vent cap 66. The pressure-based vent cap 66 is configured to release venting when the pressure inside the inner housing is greater than a predetermined pressure.

[0084] Now referring to Figure 3 , the cylindrical battery pack cell 110 includes a tubular housing 114, a cover portion 118 including a positive terminal 120, and a bottom portion 122. A battery pack cell stack 126 (e.g., jellyroll) is disposed in the tubular housing 114. External tabs 128 and 132 connect the cathode and anode electrodes to the positive terminal 120 and the negative terminal (e.g., on the bottom portion 122).

[0085] Now referring to Figure 4A and Figure 4B , a steel plate is rolled or formed into a tube 210 (e.g., cylindrical or prismatic shape with end openings), a welded seam, and the tube 210 is hardened. In Figure 4A , during induction welding of the tube 210, current flows through an induction coil 224 wound around the tube 210. The current generates a time-varying magnetic field that heats the tube 210. Welding rolls 226 press opposite sides 212 of the tube 210 together to form a seam weld 230 that closes the opposite sides of the tube 210.

[0086] In Figure 4B , after seam welding, the welded tube 260 is hardened. For example, the welded tube 260 is induction heated by an induction coil 270 wound around the welded tube 260. The welded tube 260 is heated to a predetermined temperature of 900 °C to 950 °C. After heating, the welded tube 260 is quenched (e.g., using air, water, or a cooled die) to room temperature.

[0087] In some instances, roll forming is performed using cold-rolled and annealed steel having high formability. In some instances, the cold-rolled and annealed steel plate includes an outer coating such as pure nickel.

[0088] In some instances, the cold-rolled and annealed steel plate has a lean alloy composition that includes 0.02 wt% to 0.3 wt% carbon, 0.2 wt% to 2.0 wt% manganese, at least one of chromium and molybdenum in the range of 0.5 wt% to 3.0 wt%, 0.2 wt% to 2.0 wt% silicon, at least one of niobium, titanium, and vanadium in the range of 0.01 wt% to 0.2 wt%, and iron (and optionally other materials for the balance of the composition).

[0089] In some instances, the outer shell has a martensitic microstructure for room temperature strength and one or more chromium carbides for high temperature performance. In some instances, the carbide fraction is from 1.0 volume % to 20 volume %. In some instances, the size of the chromium carbide particles is from 50 nm to 500 nm. In some instances, the chromium content of the carbide is from 5 wt% to 52 wt%.

[0090] In some instances, the weld of the welded pipe has a hardness difference of less than 50 HV (Vickers pyramid number) between the weld and the bulk steel. In some instances, the strength of the weld is as high as that of the bulk steel. In some instances, the outer shell has high strength at room temperature. In some instances, the minimum tensile strength of the outer shell is 800 MPa at room temperature and 300 MPa at 600 °C. In some instances, the outer shell has a strength of 800 MPa to 2 GPa at room temperature. In some instances, the outer shell has a strength of 1200 MPa to 2 GPa at room temperature. In some instances, the outer shell has a strength of 1500 MPa to 2 GPa at room temperature.

[0091] In some instances, the outer shell can operate at high temperatures without significant loss of strength. In some instances, the steel contains Cr / Mo-rich alloy carbides (e.g., having a size from 50 nm to 500 nm) for strengthening at high temperatures. Cr and / or Mo are added to increase hardenability, which allows the use of air (providing a slower cooling rate) instead of water as the quenching medium to minimize distortion. In some instances, the lean alloy composition maintains an overall thermal conductivity > 30 W / mK.

[0092] Now referring to Figure 5 , a method for manufacturing a battery outer shell is shown. At 310, a cold-rolled and annealed steel sheet is rolled and / or formed into a cylindrical or prismatic tube. At 314, the edges of the tube are welded to form the weld of the tubular outer shell.

[0093] At 318, the tubular outer shell is hardened. In some instances, the tubular outer shell is austenitized by using induction heating to heat the tubular outer shell and soaking for a predetermined soaking period. In some instances, the predetermined soaking period is from 1 second to 60 seconds. In some instances, the predetermined soaking period is from 4 seconds to 20 seconds. At 320, the tubular outer shell is quenched after rapid heating to form a martensitic microstructure with a fine dispersion of chromium carbides. At 322, the bottom portion of the outer shell is mechanically crimped, brazed, or welded (e.g., high frequency or laser welding) to one end of the tubular outer shell. Subsequently, the battery cells of the battery pack are arranged in the outer shell, the terminals are connected, and the cover portion is attached.

[0094] Now referring to Figures 6A to 6C , a scanning electron microscope image of the tubular outer shell during manufacturing is shown. At Figure 6AIn [reference], a tubular shell (ultimate strength of ~600 MPa) before hardening is shown. In Figure 6B In [reference], a tubular shell (ultimate strength of ~1700 MPa) after hardening is shown. In Figure 6C In [reference], the steel contains Cr-rich M7C3 carbides to improve high-temperature strength.

[0095] Now referring to Figure 7A and Figure 7B , simulations (e.g., performed using ) show the estimated phase volume fractions of the shell as a function of temperature. The simulations indicate that alloy carbide #1 and alloy carbide #2 remain in the matrix until the temperature rises to 800 °C.

[0096] Now referring to Figure 8A and Figure 8B , steel 410 may include a coating 414 (e.g., such as nickel) on its outer surface to improve corrosion resistance to the electrolyte during use. In Figure 8A , pinholes may occur in the coating 414. Without the induction heating and hardening steps described herein, the electrolyte contacts the steel 410 and causes corrosion. After the induction heating and hardening steps, the coating 414 diffuses into the steel 410 (as shown in Figure 8B ) to form an alloy diffusion layer 416 (e.g., an iron-nickel alloy) near the interface therebetween. The iron-nickel diffusion layer provides enhanced corrosion resistance in the coating pinholes 420. Thus, hardening of the steel 410 improves the coating consistency and corrosion resistance (e.g., especially at the coating pinholes 420).

[0097] Now referring to Figures 9A to 9C , improvements in the welding quality are shown respectively after welding of the tubular shell, after heating to austenitization, and after quenching and hardening. After welding (as shown in Figure 9A ), the material in the middle of the weld is melted and hardened. The region adjacent to the weld is thermally affected (e.g., softened due to heat). The outer region includes massive steel with little or no change in hardness. In Figure 9B , the tubular shell is heated to austenitization. After quenching and hardening (as shown in Figure 9C ), the hardness of the tubular shell is more uniform compared to Figure 9A . Austenitization before quenching improves the microstructure of the weld, including the fusion zone and the heat-affected zone, thereby increasing toughness and hardness.

[0098] The foregoing description is merely exemplary and is in no way intended to limit the disclosure, its application, or uses. The broad teachings of the disclosure can be implemented in a variety of forms. Thus, while the disclosure includes particular examples, the true scope of the disclosure should not be so limited since other modifications will become apparent upon study of the drawings, the specification, and the following claims. It should be understood that one or more steps within a method may be performed in a different order (or concurrently) without altering the principles of the disclosure. Further, although each of the embodiments is described above as having certain features, any one or more of the features described with respect to any one embodiment of the disclosure may be implemented in and / or combined with the features of any other embodiment, even if not explicitly described in combination. In other words, the described embodiments are not mutually exclusive, and permutations of one or more of the embodiments are still within the scope of the disclosure.

[0099] Spatial and functional relationships between elements (e.g., between modules, circuit elements, semiconductor layers, etc.) are described using a variety of terms, including “connected,” “engaged,” “coupled,” “adjacent,” “next to,” “on top of,” “on,” “under,” and “disposed.” Unless explicitly described as “direct,” when a relationship between a first element and a second element is described in the foregoing disclosure, that relationship may be a direct relationship in which no other intervening elements exist between the first and second elements, or an indirect relationship in which one or more intervening elements exist (spatially or functionally) between the first and second elements. The phrase “at least one of A, B, and C” as used herein should be construed to mean a logical (A or B or C) using a non-exclusive logical OR and should not be construed to mean “at least one of A, at least one of B, and at least one of C.”

Claims

1. A method for manufacturing a tubular housing for a battery pack battery, comprising: Rolling a steel plate into a tubular shape, wherein the steel comprises: 0.02 to 0.3 wt% carbon, 0.2 to 2.0 wt% manganese, At least one of 0.5 wt% to 3.0 wt% chromium and molybdenum, 0.2 wt% to 2.0 wt% silicon, At least one of 0.01 wt% to 0.2 wt% niobium, titanium, and vanadium, and Iron; Welding the sides of the tubular body to form a weld; Heating the tubular body to a temperature of 900 °C to 950 °C; And Quenching the tubular body.

2. The method according to claim 1, further comprising attaching a bottom portion to one end of the tubular body.

3. The method according to claim 1, wherein after quenching, the tubular body has a martensitic microstructure.

4. The method according to claim 1, wherein the tubular body comprises one or more chromium carbides having a size of 50 nm to 500 nm.

5. The method according to claim 4, wherein after quenching, the fraction of one or more chromium carbides in the tubular body is 1.0 vol% to 20 vol%.

6. The method according to claim 4, wherein after quenching, the weight of one or more chromium carbides in the tubular body is 5 wt% to 52 wt%.

7. The method according to claim 1, wherein the tubular body has a minimum tensile strength of 800 MPa at room temperature and a minimum tensile strength of 300 MPa at 600 °C.

8. The method according to claim 1, wherein the tubular housing has one of a cylindrical cross-section and a prismatic cross-section.

9. The method according to claim 1, wherein the maximum hardness difference between the weld seam and the steel of the tubular body that is not affected by heat during welding is less than 50 HV.

10. The method according to claim 1, wherein the steel comprises a nickel coating and an iron-nickel alloy layer disposed between the nickel coating and the steel after quenching.

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